Knockdown of CXCL5 inhibits the invasion, metastasis and stemness of bladder cancer lung metastatic cells by downregulating CD44.

In our previous studies, we found that T24 lung metastatic cancer cells showed high invasion and metastasis abilities and cancer stem cell characteristics compared with T24 primary cancer cells. By screening for the expression of CXC chemokines in both cell lines, we found that CXCL5 is highly expressed in T24-L cells. The aim of this study is to shed light on the relationship of CXCL5 with epithelial-mesenchymal transition (EMT) and cancer stem cells (CSCs). RNAi technology was used to decrease CXCL5 expression in the T24-L cell line, and the EMT and CSCs of the shCXCL5 group and the control group were compared. The CXCR2 inhibitor SB225002 was used to inhibit the receptor of CXCL5 to determine the effect of the CXCL5/CXCR2 axis. The knockdown of CXCL5 expression in T24-L cells reduced their EMT and CSC characteristics. RT-PCR and Western blot analyses revealed the downregulation of N-cadherin, Vimentin and CD44. In addition, when CD44 expression was knocked down, the EMT ability of the cells was also inhibited. This phenomenon was most pronounced when both CXCL5 and CD44 were knocked down. CXCL5 and CD44 can affect the EMT and stem cell capacity of T24-L cells through some interaction.

Vimentin Promotes the Aggressiveness of Triple Negative Breast Cancer Cells Surviving Chemotherapeutic Treatment.

Tremendous data have been accumulated in the effort to understand chemoresistance of triple negative breast cancer (TNBC). However, modifications in cancer cells surviving combined and sequential treatment still remain poorly described. In order to mimic clinical neoadjuvant treatment, we first treated MDA-MB-231 and SUM159-PT TNBC cell lines with epirubicin and cyclophosphamide for 2 days, and then with paclitaxel for another 2 days. After 4 days of recovery, persistent cells surviving the treatment were characterized at both cellular and molecular level. Persistent cells exhibited increased growth and were more invasive in vitro and in zebrafish model. Persistent cells were enriched for vimentinhigh sub-population, vimentin knockdown using siRNA approach decreased the invasive and sphere forming capacities as well as Akt phosphorylation in persistent cells, indicating that vimentin is involved in chemotherapeutic treatment-induced enhancement of TNBC aggressiveness. Interestingly, ectopic vimentin overexpression in native cells increased cell invasion and sphere formation as well as Akt phosphorylation. Furthermore, vimentin overexpression alone rendered the native cells resistant to the drugs, while vimentin knockdown rendered them more sensitive to the drugs. Together, our data suggest that vimentin could be considered as a new targetable player in the ever-elusive status of drug resistance and recurrence of TNBC.

Exosomal Vimentin from Adipocyte Progenitors Protects Fibroblasts against Osmotic Stress and Inhibits Apoptosis to Enhance Wound Healing.

Mechanical stress following injury regulates the quality and speed of wound healing. Improper mechanotransduction can lead to impaired wound healing and scar formation. Vimentin intermediate filaments control fibroblasts' response to mechanical stress and lack of vimentin makes cells significantly vulnerable to environmental stress. We previously reported the involvement of exosomal vimentin in mediating wound healing. Here we performed in vitro and in vivo experiments to explore the effect of wide-type and vimentin knockout exosomes in accelerating wound healing under osmotic stress condition. Our results showed that osmotic stress increases the size and enhances the release of exosomes. Furthermore, our findings revealed that exosomal vimentin enhances wound healing by protecting fibroblasts against osmotic stress and inhibiting stress-induced apoptosis. These data suggest that exosomes could be considered either as a stress modifier to restore the osmotic balance or as a conveyer of stress to induce osmotic stress-driven conditions.

Mechanical and Non-Mechanical Functions of Filamentous and Non-Filamentous Vimentin.

Intermediate filaments (IFs) formed by vimentin are less understood than their cytoskeletal partners, microtubules and F-actin, but the unique physical properties of IFs, especially their resistance to large deformations, initially suggest a mechanical function. Indeed, vimentin IFs help regulate cell mechanics and contractility, and in crowded 3D environments they protect the nucleus during cell migration. Recently, a multitude of studies, often using genetic or proteomic screenings show that vimentin has many non-mechanical functions within and outside of cells. These include signaling roles in wound healing, lipogenesis, sterol processing, and various functions related to extracellular and cell surface vimentin. Extracellular vimentin is implicated in marking circulating tumor cells, promoting neural repair, and mediating the invasion of host cells by viruses, including SARS-CoV, or bacteria such as Listeria and Streptococcus. These findings underscore the fundamental role of vimentin in not only cell mechanics but also a range of physiological functions. Also see the video abstract here https://youtu.be/YPfoddqvz-g.

The type III intermediate filament vimentin regulates organelle distribution and modulates autophagy.

The cytoskeletal protein vimentin plays a key role in positioning of organelles within the cytosol and has been linked to the regulation of numerous cellular processes including autophagy, however, how vimentin regulates autophagy remains relatively unexplored. Here we report that inhibition of vimentin using the steroidal lactone Withaferin A (WFA) causes vimentin to aggregate, and this is associated with the relocalisation of organelles including autophagosomes and lysosomes from the cytosol to a juxtanuclear location. Vimentin inhibition causes autophagosomes to accumulate, and we demonstrate this results from modulation of mechanistic target of rapamycin (mTORC1) activity, and disruption of autophagosome-lysosome fusion. We suggest that vimentin plays a physiological role in autophagosome and lysosome positioning, thus identifying vimentin as a key factor in the regulation of mTORC1 and autophagy.

Vimentin on the move: new developments in cell migration.

The vimentin gene ( VIM) encodes one of the 71 human intermediate filament (IF) proteins, which are the building blocks of highly ordered, dynamic, and cell type-specific fiber networks. Vimentin is a multi-functional 466 amino acid protein with a high degree of evolutionary conservation among vertebrates. Vim -/- mice, though viable, exhibit systemic defects related to development and wound repair, which may have implications for understanding human disease pathogenesis. Vimentin IFs are required for the plasticity of mesenchymal cells under normal physiological conditions and for the migration of cancer cells that have undergone epithelial-mesenchymal transition. Although it was observed years ago that vimentin promotes cell migration, the molecular mechanisms were not completely understood. Recent advances in microscopic techniques, combined with computational image analysis, have helped illuminate vimentin dynamics and function in migrating cells on a precise scale. This review includes a brief historical account of early studies that unveiled vimentin as a unique component of the cell cytoskeleton followed by an overview of the physiological vimentin functions documented in studies on Vim -/- mice. The primary focus of the discussion is on novel mechanisms related to how vimentin coordinates cell migration. The current hypothesis is that vimentin promotes cell migration by integrating mechanical input from the environment and modulating the dynamics of microtubules and the actomyosin network. These new findings undoubtedly will open up multiple avenues to study the broader function of vimentin and other IF proteins in cell biology and will lead to critical insights into the relevance of different vimentin levels for the invasive behaviors of metastatic cancer cells.

Repressor activator protein 1-promoted colorectal cell migration is associated with the regulation of Vimentin.

Repressor activator protein 1 plays important roles in telomere protection, while repressor activator protein 1 binds to extra-telomeric DNA and exerts the function as a transcriptional regulator. Previous study showed that repressor activator protein 1 regulates the transcriptional activity of nuclear factor-κB, and it was highly expressed in breast cancer tissues; however, the clinical significance of repressor activator protein 1 expression in cancer remains to be elucidated. In this study, we discovered that repressor activator protein 1 was highly expressed in colorectal cancer tissues. High expression of repressor activator protein 1 was significantly correlated with poor prognosis and distant metastasis. Knockdown of repressor activator protein 1 in colorectal cancer cells did not affect cell proliferation or colony formation, but dramatically decreased cell migration and F-actin-enriched membrane protrusions. Microarray screening revealed that Vimentin was downregulated after repressor activator protein 1 knockdown, which was validated by analysis of a colorectal cancer dataset. Furthermore, knockdown of Vimentin attenuated repressor activator protein 1-enhanced cell migration. Thus, our study suggests that repressor activator protein 1 is a prognostic marker and a potential target for colorectal cancer therapy.

Rab7a regulates cell migration through Rac1 and vimentin.

Rab7a, a small GTPase of the Rab family, is localized to late endosomes and controls late endocytic trafficking. The discovery of several Rab7a interacting proteins revealed that Rab7a function is closely connected to cytoskeletal elements. Indeed, Rab7a recruits on vesicles RILP and FYCO that are responsible for the movement of Rab7a-positive vesicles and/or organelles on microtubule tracks, but also directly interacts with Rac1, a fundamental regulator of actin cytoskeleton, and with peripherin and vimentin, two intermediate filament proteins. Considering all these interactions and, in particular, the fact that Rac1 and vimentin are key factors for cellular motility, we investigated a possible role of Rab7a in cell migration. We show here that Rab7a is needed for cell migration as Rab7a depletion causes slower migration of NCI H1299 cells affecting cell velocity and directness. Rab7a depletion negatively affects adhesion and spreading onto fibronectin substrates, altering ß1-integrin activation, localization and intracellular trafficking, and myosin X localization. In fact, Rab7a-depleted cells show 40% less filopodia and active integrin accumulates at the leading edge of migrating cells. Furthermore, Rab7a depletion decreases the amount of active Rac1 but not its abundance and reduces the number of cells with vimentin filaments facing the wound, indicating that Rab7a has a role in the orientation of vimentin filaments during migration. In conclusion, our results demonstrate a key role of Rab7a in the regulation of different aspects of cell migration.

Visualizing Epithelial-Mesenchymal Transition Using the Chromobody Technology.

The epithelial-mesenchymal transition (EMT) is a complex cellular program involved in the progression of epithelial cancers to a metastatic stage. Along this process, epithelial traits are repressed in favor of a motile mesenchymal phenotype. A detailed characterization and monitoring of EMT-related processes is required for the design of screening strategies needed to develop novel antimetastatic therapies. Overexpression of the canonical EMT biomarker vimentin correlates with increased tumor growth and invasiveness, as well as with reduced patient survival across various epithelial cancers. Moreover, recent findings have demonstrated an active role of vimentin in regulating and reorganizing the cellular architecture toward a migratory and invasive phenotype. However, current studies suffer from a lack of appropriate methods to trace the induction and dynamics of vimentin in cell-based assays. Recently, we have reported a novel intrabody (chromobody)-based approach to study the spatiotemporal organization of endogenous vimentin upon induction of EMT by high-content imaging. In this review, we discuss the relevance of the chromobody technology with regard to the visualization of EMT-related processes in living systems. Cancer Res; 76(19); 5592-6. ©2016 AACR.

Role of TWIST2, E-cadherin and Vimentin in epithelial ovarian carcinogenesis and prognosis and their interaction in cancer progression.

UNLABELLED: Globally, most patients are at late-stage when they have been diagnosed with ovarian cancer. Investigating the potential mechanisms involved in tumor progression and prognosis is essential for improving treatment options, outcomes, and survival. OBJECTIVE: This study elucidated the clinico-pathological significance of TWIST2 and the relationship of TWIST2, E-cadherin, and Vimentin expression in the progression and prognosis of epithelial ovarian cancer (EOC). MATERIALS AND METHODS: Immunohistochemical staining was used to quantify the expression and relevance of TWIST2, E-cadherin, and Vimentin in 103 ovarian specimens, including 30 cases of benign ovarian tumors, 30 cases of borderline ovarian tumors, and 43 cases of EOC. RESULTS: The expression of TWIST2 in the cytoplasm may help to maintain characteristics of epithelial cancer cells with E-cadherin normal membranous expression, while nuclear TWIST2 induces tumor translation front with membranous expression of Vimentin, which eventually promotes cancer metastasis. Moreover, the upregulation of TWIST2 was also related to the aberrant expression of E-cadherin and the increased expression of Vimentin, which were reported as important indicators of epithelial-mesenchymal transition (EMT). DISCUSSION: The data suggested that co-expression of TWIST2/Vimentin was an independent prognostic indicator for both overall survival and disease-free survival by multivariate Cox proportional hazards model. TWIST2 regulates EMT by depriving the epithelial cell phenotype of E-cadherin and endowing the mesenchymal cell phenotype with Vimentin, which may be involved in the progression and prognosis of ovarian cancer, and TWIST2/Vimentin co-expression might be a novel indicator with prognostic potential in EOC patients.

Interstitial fluid pressure regulates collective invasion in engineered human breast tumors via Snail, vimentin, and E-cadherin.

Many solid tumors exhibit elevated interstitial fluid pressure (IFP). This elevated pressure within the core of the tumor results in outward flow of interstitial fluid to the tumor periphery. We previously found that the directionality of IFP gradients modulates collective invasion from the surface of patterned three-dimensional (3D) aggregates of MDA-MB-231 human breast cancer cells. Here, we used this 3D engineered tumor model to investigate the molecular mechanisms underlying IFP-induced changes in invasive phenotype. We found that IFP alters the expression of genes associated with epithelial-mesenchymal transition (EMT). Specifically, the levels of Snail, vimentin, and E-cadherin were increased under pressure conditions that promoted collective invasion. These changes in gene expression were sufficient to direct collective invasion in response to IFP. Furthermore, we found that IFP modulates the motility and persistence of individual cells within the aggregates, which are also influenced by the expression levels of EMT markers. Together, these data provide insight into the molecular mechanisms that guide collective invasion from primary tumors in response to IFP.

Cells activated for wound repair have the potential to direct collective invasion of an epithelium.

Mechanisms regulating how groups of cells are signaled to move collectively from their original site and invade surrounding matrix are poorly understood. Here we develop a clinically relevant ex vivo injury invasion model to determine whether cells involved in directing wound healing have invasive function and whether they can act as leader cells to direct movement of a wounded epithelium through a three-dimensional (3D) extracellular matrix (ECM) environment. Similar to cancer invasion, we found that the injured cells invade into the ECM as cords, involving heterotypical cell-cell interactions. Mesenchymal cells with properties of activated repair cells that typically locate to a wound edge are present in leader positions at the front of ZO-1-rich invading cords of cells, where they extend vimentin intermediate filament-enriched protrusions into the 3D ECM. Injury-induced invasion depends on both vimentin cytoskeletal function and MMP-2/9 matrix remodeling, because inhibiting either of these suppressed invasion. Potential push and pull forces at the tips of the invading cords were revealed by time-lapse imaging, which showed cells actively extending and retracting protrusions into the ECM. This 3D injury invasion model can be used to investigate mechanisms of leader cell-directed invasion and understand how mechanisms of wound healing are hijacked to cause disease.

Cytokinetic Failure-induced Tetraploidy Develops into Aneuploidy, Triggering Skin Aging in Phosphovimentin-deficient Mice.

Tetraploidy, a state in which cells have doubled chromosomal sets, is observed in ∼20% of solid tumors and is considered to frequently precede aneuploidy in carcinogenesis. Tetraploidy is also detected during terminal differentiation and represents a hallmark of aging. Most tetraploid cultured cells are arrested by p53 stabilization. However, the fate of tetraploid cells in vivo remains largely unknown. Here, we analyze the ability to repair wounds in the skin of phosphovimentin-deficient (VIM(SA/SA)) mice. Early into wound healing, subcutaneous fibroblasts failed to undergo cytokinesis, resulting in binucleate tetraploidy. Accordingly, the mRNA level of p21 (a p53-responsive gene) was elevated in a VIM(SA/SA)-specific manner. Disappearance of tetraploidy coincided with an increase in aneuploidy. Thereafter, senescence-related markers were significantly elevated in VIM(SA/SA) mice. Because our tetraploidy-prone mouse model also exhibited subcutaneous fat loss at the age of 14 months, another premature aging phenotype, our data suggest that following cytokinetic failure, a subset of tetraploid cells enters a new cell cycle and develops into aneuploid cells in vivo, which promote premature aging.

Oncogenes induce a vimentin filament collapse mediated by HDAC6 that is linked to cell stiffness.

Oncogenes deregulate fundamental cellular functions, which can lead to development of tumors, tumor-cell invasion, and metastasis. As the mechanical properties of cells govern cell motility, we hypothesized that oncogenes promote cell invasion by inducing cytoskeletal changes that increase cellular stiffness. We show that the oncogenes simian virus 40 large T antigen, c-Myc, and cyclin E induce spatial reorganization of the vimentin intermediate filament network in cells. At the cellular level, this reorganization manifests as increased width of vimentin fibers and the collapse of the vimentin network. At nanoscale resolution, the organization of vimentin fibers in these oncogene-expressing cells was more entangled, with increased width of the fibers compared with control cells. Expression of these oncogenes also resulted in up-regulation of the tubulin deacetylase histone deacetylase 6 (HDAC6) and altered spatial distribution of acetylated microtubules. This oncogene expression also induced increases in cellular stiffness and promoted the invasive capacity of the cells. Importantly, HDAC6 was required and sufficient for the structural collapse of the vimentin filament network, and was required for increased cellular stiffness of the oncogene-expressing cells. Taken together, these data are consistent with the possibility that oncogenes can induce cellular stiffness via an HDAC6-induced reorganization of the vimentin intermediate filament network.

Expression of vimentin and gfap protein of cerebral cortex and its impact on corticogenesis disorder as a result of 2-methoxyethanol / Expresión de vimentina y proteína gfap de la corteza cerebral y su impacto en el trastorno de corticogenesis como producto del 2-metoxietanol

One of the plastic base material, widely used in the plastics industry in various countries, is a ester phthalate. These compounds will be oxidizedin the body to 2-methoxyethanol (2-ME). Effect of 2-ME on human health and the environment depends on the number, duration and frequency of exposure. 2-ME and its metabolites in the body can damage cells and tissues. The body can be exposed by 2-ME through the air, water and soil. Western blot results showed that the protein Vimentin was detectable in the control group at GD-11 to 17, meanwhile GFAP protein was detachable in the control group atGD- 12 to GD-18. After administration 2-ME, the expression of Vimentinprotein were changed, and started at GD- 12 up to GD-18. whereas the expression of GFAP protein began at GD-11 up to GD-17. The Changes on timetable protein expression of Vimentin and GFAP affect corticogenesis disorder. The disorder caused by the existence of these proteins as a result of 2-Methoxyethanol. Disorder of corticogenesis process were sub-plate and cortical plate of the cerebral cortex of fetus brains of mice at GD-18. Generally, it can be concluded that changes inprotein expression of Vimentin and GFAP causedby 2-ME. The Vimentin more important during the period of fetal brain development. GFAP and Vimentin is a protein involved in response to damage caused by a teratogenic agent, so that cells in the cerebral cortex, has dedifferentiation.

Uno de los materiales a base de plástico, ampliamente utilizado en la industria en varios países, es un éster de ftalato. Estos compuestos se oxidan en el cuerpo a 2-metoxietanol (2-ME). El efecto del 2-ME en la salud humana y el medio ambiente depende de la cantidad, duración y frecuencia de exposición. El 2-ME y sus metabolitos en el cuerpo puede dañar las células y tejidos. El cuerpo puede ser expuesto al 2-ME a través del aire, agua y suelo. Los resultados de Western blot mostraron que la proteína vimentina fue detectable en el grupo de control en GD-11 a 17, por su parte proteína GFAP fue detectable en el grupo de control en GD-12 a GD-18. Después de la administración de 2-ME, la expresión de la proteína vimentina cambió, y comenzó a detectarse en GD-12 hasta GD-18, mientras que la expresión de la proteína GFAP se inició en GD-11 hasta GD-17. Los cambios en el momento de expresión de las proteínas vimentina y GFAP afectan produciendo trastornos de la corticogénesis. El trastorno causado por la existencia de estas proteínas como resultado de 2-metoxietanol a nivel del proceso corticogénesis fue en la subplaca y la placa cortical de la corteza cerebral del cerebro de fetos de ratones en GD-18. En general, se puede concluir que existen cambios en la expresión de las proteínas vimentina y GFAP causados por el 2-ME. La vimentina es muy importante durante el período de desarrollo del cerebro fetal. GFAP y vimentina son proteínas implicadas en la respuesta a los daños causados por un agente teratogénico, de modo que las células en la corteza cerebral presentan desdiferenciación.

Effects of formaldehyde and vimentin expression in rat skin / Efectos del formaldehído y expresión de vimentina en la piel de rata

The Wistar rats ( 9 weeks old, 180­200 g body weight) used in these trials were divided into two groups of 16 animals each (Control group and Experimental group). 100x65x100 in the sizes of the experimental group were taken into a glass vase. During the time period of 8 weeks, 5 days a week with 8 hours the inhalation of 10 ppm formaldehyde was made. Skin was removed and placed in 10% formaline. Sections were stained with Hematoxylene-Eosine, Trichrome-Masson and observed under light microscope. In this study, histopathological and immunohistochemical techniques due to the impact of the changes in formaldehyde and examined the distribution of vimentin.

En este ensayo se utilizaron ratas Wistar (9 semanas de edad, 180-200 g de peso corporal) que se dividieron en dos grupos de 16 animales cada uno (grupos control y experimental). Los animales del grupo experimental fueron colocados en un vaso de vidrio de tamaño 100x65x100. Durante un período de tiempo de 8 semanas, 5 días a la semana con 8 horas se expuso a la inhalación de 10 ppm de formaldehído. Se retiró la piel y se colocó en formalina al 10%. Las secciones fueron teñidas con Hematoxilina-Eosina y Tricrómico de Masson, y fueron observadas al microscopio óptico. Las técnicas histopatológicas e inmunohistoquímicas y el impacto en la piel provocado por el formaldehído permitieron examinar la expresión de vimentina.

The effects of nicotine on the incisive teeth and expression of vimentin in rats / Efectos de la nicotina sobre los dientes incisivos y la expresión de vimentina en ratas

Nicotine is an alkaloid toxic effects of oral cavity. In this study,14 adult Sprague-Dawley rats weighing 230-260 mg (+/-10 mg) were used as experimental animal. The rats of experimental group (n=6) were nicotinized systemically with nicotine sulphate, 2mg/kg subcutaneously, daily in period of 28 days. Pulp, alveolar bone tissue, periodontal membrane and gingival epithelial junction were investigated in these regions in incisive teeth longitudinal cross-section. Thinning of the collagen fibers in the pulp tissue, vascular congestion, and inflammatory cell infiltration were observed. Mesenchymal tissues that is stained positive for vimentin lay underneath the epithelium. A strong expression of vimentin can be observed in formed periodontal ligament.

La nicotina es un alcaloide con efectos tóxicos sobre la cavidad oral. En este estudio, se utilizaron como animales de experimentación, 14 ratas Sprague-Dawley adultas con un peso entre 230-260 mg (+/- 10 mg). Las ratas del grupo experimental (n = 6) fueron expuestas a nicotina sistémicamente con sulfato de nicotina, 2mg/kg vía subcutánea al día, durante 28 días. Fueron estudiadas la pulpa, tejido óseo alveolar, membrana periodontal y la unión del epitelio gingival en los dientes incisivos en secciones transversales y longitudinales. Se observó un adelgazamiento de las fibras de colágeno, congestión vascular e infiltración de células inflamatorias en el tejido de la pulpa. Los tejidos mesenquimales que tiñeron positivamente para vimentina se ubicaron debajo del epitelio. Una fuerte expresión de vimentina se pudo observar en el ligamento periodontal.

Circulating tumour cells and cancer stem cells: a role for proteomics in defining the interrelationships between function, phenotype and differentiation with potential clinical applications.

Research on the discovery and implementation of valid cancer biomarkers is one of the most challenging fields in oncology and oncoproteomics in particular. Moreover, it is generally accepted that an evaluation of cancer biomarkers from the blood could significantly enable biomarker assessments by providing a relatively non-invasive source of representative tumour material. In this regard, circulating tumour cells (CTCs) isolated from the blood of metastatic cancer patients have significant promise. It has been demonstrated that localised and metastatic cancers may give rise to CTCs, which are detectable in the bloodstream. Despite technical difficulties, recent studies have highlighted the prognostic significance of the presence and number of CTCs in the blood. Future studies are necessary not only to detect CTCs but also to characterise them. Furthermore, another pathogenically significant type of cancer cells, known as cancer stem cells (CSCs) or more recently termed circulating tumour stem cells (CTSCs), appears to have a significant role as a subpopulation of CTCs. This review discusses the potential application of proteomic methodologies to improve the isolation and characterisation of CTCs and to distinguish between CTCs with a poor clinical significance and those with important biological and clinical implications.

Vimentin regulates peripheral nerve myelination.

Myelination is a complex process that requires coordinated Schwann cell-axon interactions during development and regeneration. Positive and negative regulators of myelination have been recently described, and can belong either to Schwann cells or neurons. Vimentin is a fibrous component present in both Schwann cell and neuron cytoskeleton, the expression of which is timely and spatially regulated during development and regeneration. We now report that vimentin negatively regulates myelination, as loss of vimentin results in peripheral nerve hypermyelination, owing to increased myelin thickness in vivo, in transgenic mice and in vitro in a myelinating co-culture system. We also show that this is due to a neuron-autonomous increase in the levels of axonal neuregulin 1 (NRG1) type III. Accordingly, genetic reduction of NRG1 type III in vimentin-null mice rescues hypermyelination. Finally, we demonstrate that vimentin acts synergistically with TACE, a negative regulator of NRG1 type III activity, as shown by hypermyelination of double Vim/Tace heterozygous mice. Our results reveal a novel role for the intermediate filament vimentin in myelination, and indicate vimentin as a regulator of NRG1 type III function.

Role of vimentin in the inhibitory effects of low-molecular-weight heparin on PC-3M cell adhesion to, and migration through, endothelium.

Low-molecular-weight heparin (LMWH) has been used in cancer patients with venous thromboembolic complications, resulting in a higher survival rate and an inhibitory action on experimental metastasis. In the present study, human umbilical vein endothelial cells (HUVECs) were treated with LMWH for 24 h. We found that the resulting HUVECs could significantly inhibit the highly metastatic human prostate cancer cell line (PC-3M) in terms of its adhesion to the endothelium and migration across the endothelium, according to scanning electron microscopy. We also determined the elevated levels of endothelial intercellular Ca(2+) concentration after the adhesion of PC-3M cells to HUVECs was greatly reduced by incubation with LMWH. Using proteomics, we surveyed the global protein changes in HUVECs after LMWH treatment and identified four down-regulated proteins that were possible isoforms of cytoskeletal vimentin intermediate filaments, cartilage-derived C-type lectin, and serine/threonine protein phosphatase 1ß (PP-1B). LMWH affected the morphology of vimentin and the expression levels of α(v) integrin and PP-1B in HUVECs bound to PC-3M cells. Vimentin assists in the adhesion of PC-3M cells, which was confirmed by short interfering RNA experiments. Furthermore, the direct binding of purified vimentin protein with LMWH was detected with surface plasmon resonance methods. However, when we used fluorescence-labeled heparin for 24 h to identify whether this binding occurred within cells, heparin was distributed principally around endothelial cells. Taken together, these findings suggest that the monoincubation of LMWH with HUVECs could inhibit PC-3M cell adhesion to, and migration through, endothelium. LMWH's regulation of vimentin plays a role in the antimetastatic action.